Comment by skeledrew

Because something isn't widely adopted doesn't mean that it's dead. Microsoft continues to use and support OLE today, and there's a non-zero number of non-Microsoft-affiliated persons out there using it (I've seen forums with users asking how to do X regarding it).

KParts too is very much alive, as it's a core part of KDE Frameworks, which is used to build Plasma. And I know for a fact it works very well because I'm a Kubuntu user (11 years).